Zahn became the youngest bowler ever to be inducted into the USBC Hall of Fame until Nelson Burton Jr.'s induction in 1981. A one-time USBC Open Championships eagle winner, he was a teenage sensation in Milwaukee, reaching a 222 league average in 1960-61. At age 19, he finished ninth in the All-Star tournament, the youngest ever to finish that high. He later moved to Tempe where he operated a 24-lane center. The 14-time PBA titlist and PBA Hall of Famer rolled the first 300 game ever in the Hall of Fame Tournament in 1989.